Bismuth-Centered Radical Species: Access and Applications in ­Organic Synthesis

Abstract Recent advances in the isolation of tamed bismuth radicals and the selective in situ generation of highly reactive bismuth radicals have set the stage for the application of these compounds in organic and organometallic synthesis and catalysis. Here, we provide a summary of the methodological approaches in the field. Important strategies for accessing bismuth radical species are presented and key examples of their applications in organic synthesis are outlined, highlighting how this class of compounds has emerged as new set of valuable tools for synthetic practitioners. 1 Introduction 2 Generation of Bismuth Radical Species by Homolysis 2.1 Temperature-Induced Homolysis 2.2 Light-Induced Homolysis 2.3 Light-/Temperature-Induced Bi–C Homolysis of Polar Oxidative Addition Complexes 3 Applications of Bismuth-Centered Radical Species in Organic Synthesis 3.1 Bismuth-Catalyzed Cycloisomerization of Iodo Olefins 3.2 Controlled Radical Polymerization Reactions 3.3 Bismuth-Promoted Pn–Pn and C–S Coupling 3.4 Bismuth-Catalyzed Dehydrocoupling of Silanes with TEMPO 3.5 Bismuth-Catalyzed C–N Coupling with Redox-Active Electrophiles 3.6 Bismuth-Catalyzed Giese-Type Coupling Reactions 3.7 Oxidative Addition of Aryl Electrophiles to Photoactive Bismuthinidenes 4 Conclusions